Solid paste and method of making same

ABSTRACT

Solid paste composition is formed by the steps of (a) mixing the ingredients of a water soluble or water miscible paste component with the same solvent alone or with its mixture with water, (b) adding further ingredients consisting of (i) the condensate of sorbite and benzaldehyde as forming agent, and (ii) alkyl-pyrrolidone as solution accelerator for the gel forming agent, (c) dissolving the aforesaid ingredients by uniformly heating and stirring, and (d) solidifying said ingredients by pouring into a given mold, cooling and recovering the so-obtained solid paste composition.

CROSS-REFERENCE TO PRIOR APPLICATION

This application is a continuation of application Ser. No. 434,409 filedJan. 18, 1974, now abandoned, while in turn is a continuation-in-part ofApplication Ser. No. 264,826, filed on June 21, 1972, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the forming of solid paste by using thecondensate of a polyalcohol, such as sorbite, and benzaldehyde as gelforming agent. The solution accelerator for said agent and, inparticular, for the solid paste, is formed efficiently in the shortestpossible time. In consideration of the fact that the accelerator has agreat effect on the quality of products or manufacturing process, thesolution accelerator is used which shows greatly high workability whenused alone or with dimethylformamide.

2. The Prior Art

The prior art reference U.S. Pat. No. 2,658,045is characterized in thatpolyvinyl pyrrolidone (P.V.P.) is treated and gelled by persulfate. Thatis, the P.V.P. is used as a gelling agent in the prior art reference. Inthe present invention, however, the condensate of sorbitol andbenzaldehyde is employed as a gelling agent and a sufficient soliditycan be given to this gelling agent without using the P.V.P. After all,the P.V.P. is used only as an adhesive in this invention. Besides, thepresent invention finds it unnecessary to use watermiscible persulfatein forming gelling agents.

In prior art U.S. Pat. No. 3,071,513, several kinds of solvent andadhesive are mixed to seal a capsule while a mixture of componentssimilar to the said U.S. Pat. No. 3,071,513 is used to adhere paper,cloth, lumber and the like in the present invention. Thus, the presentinvention completely differs in purpose and content from this patent.

Prior art U.S. Pat. No. 3,504,746 is characterized in that the P.V.P. istreated and gelled by a redox catalyst of reducing agent or peroxide orboth mixed. That is, the P.V.P. is used as a gelling agent in U.S. Pat.No. 3,504,746.

In the present invention, however, the condensate of sorbitol andbenzaldehyde is employed as a gelling agent and a sufficient soliditycan be given to this gelling agent without using the P.V.P.

After all, the P.V.P. is used only as an adhesive in this invention, andthis invention finds it unnecessary to use a redox catalyst of reducingagent and peroxide in forming gelling agents. Thus, the presentcomposition invention is neither suggested nor taught by this prior artnor by any of the other prior art, either alone or in combination. Onlythe use of the P.V.P. is common to the present invention and the priorart inventions. The P.V.P. of the present invention is mixed for thepurpose completely different from that of the prior art. In other words,P.V.P. is employed only as an adhesive in the present invention.Moreover, none of the reducing agents, peroxides or persulfates, whichare main components of the prior art, are used in the present invention.

SUMMARY OF THE INVENTION

According to the present invention, polyvinylpyrrolidone or the waterdispersive copolymer of vinyl acetate and vinylpyrrolidone or the like,and a lower alkanol such as isopropyl alcohol, ethanol, or the like, areused as known water soluble or miscible paste component and solventcomponent, respectively, of a solid paste composition. Theabove-mentioned condensate of sorbite and benzaldehyde is used as a gellforming agent, and a solution accelerator is properly chosen and usedfor the dissolving of the gel forming agent, for example,alkylpyrrolidones, such as methylpyrrolidone, ethylpyrrolidone,N-methyl-2-pyrrolidone, N-methyl-pyrrolidone, N-propyl-2-pyrrolidone.Lower alkylpyrrolidones are preferred. The condensate of sorbite andbenzaldehyde is prepared according to the following method, which isdescribed hereinbelow.

Furthermore, polyvinyl alcohol and ethyl alcohol may be used as saidpaste component and solvent component, respectively.

The various ingredients of the solid paste composition of the inventionare described as follows.

Polyvinylpyrrolidone: its molecular weight, structural formula andphysical properties are as follows:

i. molecular weight: 10,000 - 400,000

ii. formula: ##STR1## iii. physical properties are well known.Properties: forms hard, transparent, lustrous films. Binds, stabilizesmany organic and inorganic compounds. Detoxifies a wide variety ofirritants. Protects, stabilizes suspensions, dispersions, emulsions.Prevents soil redeposition. Precipitates tannins. Physiologicallycompatible. Adherent to hair, smooth surfaces. Soluble in water,alcohols, some chlorinated solvents, nitroparaffins, amines.

Copolymer: its molecular weight, structural formula and physicalproperties:

i. Molecular weight: 10,000 - 400,000

ii. Formula

polyvinylpyrrolidone ##STR2##

water-dispersive vinylacetate ##STR3##

iii. Physical properties:

Form adhesive, glossy, water-removable films (water sensitivityincreases with vinylpyrrolidone content). Compatibility with manymodifiers and plasticizers permits various degrees of hygroscopitity,flexibility, abrasion resistance. Diverse physical forms offer a broadrange of compatibility with aqueous and organic solvent systems.

Polyvinyl alcohol: its molecular weight and structural formula:

i. Molecular weight: 10,000 - 300,000

ii. formula: ##STR4##

As gelling agent, benzylidene sorbitol (the condensate of benzaldehydeand sorbite) is employed and prepared from benzaldehyde and sorbite##STR5##

Other aldehydes cannot be used, except Xylitol, which however, can beused in place of sorbite. Its structure is as follows: ##STR6##

The structure of the aforementioned condensate is as follows:

Di-Benzylidene sorbitol: ##STR7## and

Tri-benzylidene sorbitol: ##STR8##

As solution accelerator alkylpyrrolidone is used, especially,N-methyl-2-pyrrolidone.

DESCRIPTION OF SPECIFIC EMBODIMENTS

The Examples which are meant to illustrate the invention are shownbelow. Unless otherwise stated herein, all parts are parts by weight,and the relationship of parts by weight to parts by volume is as that ofgrams to cubic centimeters. Temperatures are in degrees centigrade.

EXAMPLE 1.

    ______________________________________                                        Ingredients                                                                   Polyvinyl pyrrolidone 15 parts                                                Isopropyl alcohol     40 parts                                                Condensate of Sorbite and                                                     Benzaldehyde           3 parts                                                Methylpyrrolidone      5 parts                                                ______________________________________                                    

A heater equipped with a stirrer is filled up with the foregoing mixtureof ingredients, which are heated at a temperature of about 80° C and theresulting solution is stirred for about an hour under reflux.Immediately after this, the above mixture of ingredients is poured intoa given mold, and left to cool for about a half hour at roomtemperature. As a result, the ingredients are solidified into thepredetermined solid paste.

The given mold used in this example is a die, shaped in a cylindricalform, and the solid paste product has a cylindrical shape.

With the solid paste thus produced, paper of fine quality has beensealed perfectly in ten minutes.

EXAMPLE 2.

    ______________________________________                                        Ingredients                                                                   Water dispersive Copolymer of                                                 vinyl acetate and vinyl pyrrolodone                                                                   15 parts                                              Water                   20 parts                                              Ethanol                 20 parts                                              Condensate of Sorbite and                                                     Benzaldehyde             2 parts                                              Methyl pyrrolidone       5 parts                                              ______________________________________                                    

The solid paste of this blending of the foregoing ingredients has beenmade in the same manner as in Example 1. The solid paste is used onpaper of fine quality. The same result as that of Example 1 has beenobserved.

Examples of Vinylpyrrolidone / vinyl acetate copolymer are, forinstance,

polyvinylpyrrolidone / vinyl acetate S-60

    ______________________________________                                        vinylpyrrolidone       60%                                                    vinyl acetate          40%                                                    ______________________________________                                    

(made by General Aniline & Film Corp.) LUBYSCOL VA 64

    ______________________________________                                        LUBYSCOL VA 64                                                                vinylpyrrolidone       60%                                                    vinyl acetate          40%                                                    ______________________________________                                    

(made by Badische Aniline & Soda-Fabrik A.G.)

Alkylpyrrolidone including the solution accelerator used in theseExamples 1 and 2 has a high solubility for said gel-forming agent usedin this invention, and its amount to be used can be minimized. Thus,since the solution accelerator does not have a good adhering quality,for it is hard to boil and dry, it is often desirable to cut down orminimize the quantity of solution accelerator which is used.

In view of the present invention, the gel-forming agent andalkylpyrrolidone as a solution accelerator for said agent are mixed, anduniformly heated and stirred, and they are poured into the given moldand cooled to be solidified into the solid paste. Accordingly, thesolution accelerator for the gelling agent can show its efficiency toperfection.

Thus, solubility of the gel-forming agent can be made extremely high,and the agent can uniformly be dissolved. The solid paste havingsuitable solidity can be attained with only a small quantity of thesolution accelerator.

When using alkylpyrrolidone or methylpyrrolidone, especially as asolution accelerator, the dissolving force is twice that of dimethylformamide (DMF). In the present case, therefore, the solutionaccelerator can be reduced to half the quantity when DMF is used. It isalso desirable to use the solution accelerator in as little quantity aspossible for finishing adhesion quickly, since the accelerator is slowto dry.

The preferred ratio in the solid paste composition is as follows:

    ______________________________________                                        Polyvinyl pyrrolidone      Best (Most Pre-                                    Vinyl pyrrolidone Preferred Range                                                           ferred Range of                                                 vinyl acetate of Components                                                                              Components                                         ______________________________________                                        (Paste miscible with                                                          water)        10 to 40 parts                                                                             10 to 20 parts                                     Solvent       35 to 70 parts                                                                             35 to 50 parts                                     Gel-forming agent                                                                            1 to 10 parts                                                                              2 to  5 parts                                     Solution accelerator                                                                         2 to 15 parts                                                                              3 to  8 parts                                     ______________________________________                                    

In addition, the present invention makes it possible to keep out anoffensive smell of dimethylformamide and shorten drying hours insealing. After all, this invention has high workability due to the useof the solution accelerator having an extremely high solubility andwater dispersive copolymer of vinylacetate and vinylpyrrolidone and canachieve the expected objective of efficiently producing the solid pastein the shortest possible time.

In the foregoing examples, the molecular weight ratio of D-sorbite andbenzaldehyde is 1:2 in preparation of the condensate thereof. Thecondensate is prepared as follows. Two gram molecules of benzaldehydeare added to one gram molecule of D-sorbite and stirred at roomtemperature with a small quantity of 60% (Volume) sulphuric acid,resulting in a paste-like, white-colored substance.

This substance is washed in water to remove non-reactive benzaldehydetherefrom and then extracted with ether; the resulting substance iswashed once again in water, as before, and extracted with ether, andthen the ether extract is evaporated to dryness to yield awhite-colored, powdered condensate, with the formula as follows:##STR9## Condensate: Di-benzylidene sorbitol.

The condensate of one-molecule of D-sorbite and two-molecules ofbenzaldehyde is the most effective for gel-forming, and thus, it is mostdesirable to use a substance which contains this type condensate in ashigh purity as possible.

Characteristics of pure condensates are:

White-colored powder and non-resin

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principals.

What is claimed is:
 1. Solid paste composition which consistingessentially from about 10 to about 40 parts by weight of a pastecomponent miscible with water consisting essentially of a memberselected from the group consisting of polyvinyl alcohol, and copolymerof a water dispersive about 40%, vinyl acetate and about 60%vinylpyrrolidone; from about 35 to about 70 parts by weight of a solventcomponent consisting essentially of lower alkanol; from about 1 to about10 parts by weight of a gel forming agent consisting essentially of acondensate of sorbite and benzaldehyde; and from about 2 to about 15parts by weight of a solution accelerator consisting essentially ofalkylpyrrolidone for said gel forming agent.
 2. Solid paste composition,according to claim 1, wherein said alkylpyrrolidone is selected from thegroup consisting of methylpyrrolidone, ethylpyrrolidone,N-methyl-2-pyrrolidone, N-methyl-pyrrolidone, andN-propyl-2-pyrrolidone.
 3. Solid paste composition, according to claim1, wherein said paste component is a member selected from the groupconsisting of polyvinylpyrrolidone, polyvinyl alcohol, and waterdispersive copolymer of vinyl acetate and vinyl pyrrolidone; saidsolvent component consisting essentially of lower alkanol; and saidsolution accelerator is a member selected from the group consisting ofmethylpyrrolidone, ethyl-pyrrolidone, N-methyl-2-pyrrolidone,N-methyl-pyrrolidone, and N-propyl-2-pyrrolidone.
 4. Solid pastecomposition according to claim 3, wherein the paste component comprisespolyvinyl pyrrolidone, the solvent component consists essentially ofisopropyl alcohol, and the solution accelerator consists essentially ofmethyl pyrrolidone.
 5. Solid paste composition, according to claim 3,wherein the paste component consists essentially of a water dispersivecopolymer of vinylacetate and vinyl pyrrolidone, and the solventcomponent comprises a lower alkanol.
 6. Solid paste composition,according to claim 3, wherein the paste component consists essentiallyof about 15 parts polyvinyl pyrrolidone, about 40 parts isopropylalcohol, about 3 parts condensate of sorbite and benzaldehyde, and about5 parts methyl pyrrolidone, all of said parts being by weight.
 7. Solidpaste composition according to claim 3, wherein the paste componentconsists essentially of about 15 parts of a water dispersive copolymerof vinyl acetate and vinyl pyrrolidone, about 20 parts water, about 20parts ethanol, about 2 parts condensate of sorbite and benzaldehyde, andabout 5 parts methyl pyrrolidone, all of said parts being by weight. 8.Solid paste composition according to claim 1, wherein said pastecomponent is present in the range of from about 10 to 20 parts byweight.
 9. Solid paste composition according to claim 1, wherein saidsolvent is present in an amount of from about 35 to 50 parts by weight.10. Solid paste composition according to claim 1, wherein said gelforming agent is present in an amount of from about 2 to 5 parts byweight.
 11. Solid paste composition according to claim 1, wherein saidsolution accelerator is present in an amount of from about 3 to about 8parts by weight.